Since photographic light-sensitive materials generally comprise a support and photographic light-sensitive layers having electrical insulation properties, they are often susceptible to accumulation of static electricity due to contact friction against or peeling from the surface of the same or different kind of element upon their manufacture and use. Static electricity thus accumulated causes many troubles. One of the most serious troubles is that the light-sensitive emulsion layer is exposed to light by the discharge of static electricity which has been accumulated before development. When the photographic film is developed, this causes formation of dot-like spots, or branch-like or feather-like line spots thereon. These spots are so-called static marks which remarkably or, sometimes, totally mar the commercial value of the photographic film. It can be readily understood that such static marks developed on medical or industrial X-ray films, for example, lead to extremely dangerous misjudgments. Such static marks occurred in color photographic light-sensitive materials will mar the memorial value. Since such an accident appears only when the photographic light-sensitive material is developed, static mark is one of very difficult problems in this field. Such static electricity thus accumulated also causes the surface of the film to attract dust or makes it difficult to make a uniform coating to the film.
As described above, such static electricity is often accumulated in photographic light-sensitive materials upon its manufacture and use. For example, in the manufacture, static electricity is generated by contact friction between the photographic film and the roller or peeling of the support from the emulsion layer during the winding or rewinding of the photographic film. Furthermore, static electricity is generated by the separation of the base from the emulsion layer when the finished product is rewound on another reel. Moreover, static electricity is generated when an X-ray film is brought into contact with and then separated from a mechanical part or a fluorescent-sensitized paper in an automatic photographic apparatus.
In color negative films and color reversal films, static electricity is generated when they are brought into contact with and then separated from a connecting machine in a camera or a developing facility, or a rubber, metal or plastic roller bar in an automatic developing machine.
Static electricity is also generated when the photographic light-sensitive material is brought into contact with packing materials. Static marks developed by such a static electricity accumulation become more remarkable when the sensitivity and the treatment speed of the photographic light-sensitive material is increased. In recent years, the photographic light-sensitive materials have been improved more and more in its sensitivity, coating speed, photographing speed, and automatic development speed. Furthermore, the photographic light-sensitive materials have been more often subjected to exposure to low humidity. These severe handling conditions make the photographic light-sensitive materials more susceptible to static marks.
In order to eliminate such troubles due to static electricity, it is preferable that antistatic agents be incorporated in the photographic light-sensitive materials. However, as antistatic agents to be used in the photographic light-sensitive materials, antistatic agents which are commonly used in other fields cannot always be applied. The use of such antistatic agents is subject to various restrictions peculiar to the photographic light-sensitive materials. Particularly, besides being excellent in antistatic properties, such antistatic agents which may be used for the photographic light-sensitive materials must satisfy various requirements. For example, such antistatic agents must not have harmful effects on the photographic properties of the photographic light-sensitive materials such as sensitivity, fog, graininess, and sharpness; they must not deteriorate the film strength of the photographic light-sensitive materials (i.e., insusceptibility to scratch due to friction or scratching); they must not have harmful effects on the anti-adhesive property of the photographic light-sensitive materials (i.e., insusceptibility to adhesion between surfaces of the photographic light-sensitive materials or to the surface of other materials). Such antistatic agents are also required not to accelerate fatigue of the treating solution in the photographic light-sensitive materials, soil the conveying roller, and lower the adhesion between the constituent layers of the photographic light-sensitive materials. Thus, the application of antistatic agents to the photographic light-sensitive materials is subjected to a very large number of restrictions.
One of the approaches to eliminate troubles due to static electricity is to raise the electric conductivity of the surface of a light-sensitive material so that static electricity can be scattered and lost in a short period of time before being discharged.
Therefore, methods of improving the electric conductivity of the support and various coated surface layers of the photographic light-sensitive materials have heretofore been carried out. In these methods, the application of various hygroscopic materials and water-soluble inorganic salts, and some kinds of surface active agents and polymers have been attempted. Examples of known materials which have been attempted to be used include polymers as described in U.S. Pat. Nos. 2,882,157, 3,262,807, and 3,938,999, surface active agents as described in U.S. Pat. Nos. 2,982,651, 3,457,076, and 3,655,387, and metal oxides and colloid silica as described in U.S. Pat. Nos. 3,062,700 and 3,525,621.
However, most of these materials show some specificity against specific kinds of supports and photographic compositions. That is to say, these materials give good results against specific supports and photographic emulsions and other photographic constituent elements of the photographic light-sensitive materials, but may not only be no use in antistatic effect but also give harmful effects on the photographic properties when used in other supports and photographic constituent elements of the photographic light-sensitive materials.
On the other hand, there are some antistatic agents which have very excellent antistatic properties but cannot be used due to harmful effects on the photographic properties such as sensitivity, fog, graininess and sharpness of the photographic emulsion. For example, polyethylene oxide compounds are generally known to have antistatic properties.
In order to obtain satisfactory antistatic properties by the use of polyethylene oxide compounds alone, however, it is necessary to add a large amount thereof, and in so doing it often gives harmful effects on the photographic properties such as increase of fog, desensitization, and deterioration of graininess. Also upon development, it is liable to be stained, and coating at high speed causes troubles such as repelling, or the like. In particular, it has been difficult to establish a technique effectively providing antistatic properties to a light-sensitive material comprising a support coated with a photographic emulsion on both sides thereof, such as medical direct X-ray light-sensitive material, without giving harmful effects on the photographic properties. Thus, it is very difficult to apply antistatic agents to photographic light-sensitive materials. Furthermore, the use of antistatic agents is often limited.
Another approach to eliminate troubles on the photographic light-sensitive materials due to static electricity is to reduce the capability of the surface of the photographic light-sensitive material to generate static electricity so that the generation of static electricity due to friction or contact can be minimized.
To this end, the use of fluorine-containing ionic surface active agents as described in British Pat. Nos. 1,330,356 and 1,524,631, U.S. Pat. Nos. 3,666,478, 3,589,906, and 3,850,642, Japanese patent publication No. 26687/77, and Japanese patent application (OPI) Nos. 46733/74, 32322/76, 84712/78, 14224/79, 52223/73, 127974/77, and 200235/83 (the term "OPI" as used herein means an "unexamined published Japanese patent application") in the photographic light-sensitive materials have been attempted.
However, photographic light-sensitive materials containing these fluorine-containing ionic surface active agents have a static property such that when brought into contact with various materials, they generally show negative-electrification property against these materials. It is possible to reduce the capability of these photographic light-sensitive materials to generate static electricity against a rubber roller, Derlin roller, nylon bar, etc., by incorporating coating agents having positive-electrification property against these various elements in the photographic light-sensitive materials. However, it is impossible to simultaneously reduce the capability of the light-sensitive materials to generate static electricity against all these elements with which the light-sensitive materials are brought into contact. For example, if the capability of the light-sensitive materials to generate static electricity against rubber is reduced, it is usual that branch-like static marks are generated due to Derlin or the like, which is positioned at the positive side of rubber in the electrification series. On the contrary, if the capability of the light-sensitive materials to generate static electricity against Derlin is reduced, it is usual that spot-shaped static marks are generated due to rubber or the like, which is positioned at the negative side of Derlin in the electrification series. These fluorine-containing ionic surface active agents deteriorate coating properties. Furthermore, photographic light-sensitive materials containing the fluorine-containing ionic surface active agents are susceptible to change in its capability of generating static electricity during storage after manufacture. Thus, these fluorine-containing ionic surface active agents cannot be easily put into practical use with light-sensitive materials.
Furthermore, the use of fluorine-containing nonionic surface agents is disclosed in Japanese patent application (OPI) No. 61236/75 and U.S. Pat. No. 4,175,969.
In accordance with these patents, the dependence of the photographic light-sensitive materials on the elements with which they are brought into contact can be slightly reduced by adding a large amount of these surface active agents thereto. However, since the use of a large amount of these surface active agents causes a drastic reduction of sensitivity, adhesion between films and stain upon development, these surface active agents cannot be put into practical use.